21869826 has 32 divisors (see below), whose sum is σ = 49794048. Its totient is φ = 6338640.

The previous prime is 21869821. The next prime is 21869839. The reversal of 21869826 is 62896812.

It is not an unprimeable number, because it can be changed into a prime (21869821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5686 + ... + 8721.

It is an arithmetic number, because the mean of its divisors is an integer number (1556064).

Almost surely, 2^21869826 is an apocalyptic number.

21869826 is an abundant number, since it is smaller than the sum of its proper divisors (27924222).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21869826 is a wasteful number, since it uses less digits than its factorization.

21869826 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14446.

The product of its digits is 82944, while the sum is 42.

The square root of 21869826 is about 4676.5185768903. The cubic root of 21869826 is about 279.6501838899.

The spelling of 21869826 in words is "twenty-one million, eight hundred sixty-nine thousand, eight hundred twenty-six".